1. Field of the Invention
The invention relates to valve assemblies, and, more particularly, to relief valve assemblies for use in the cooling systems of internal combustion engines, and particularly marine engines.
2. Reference to Prior Art
Water cooled internal combustion engines include an engine block having a coolant conduit with an upstream portion and a downstream portion, and a valve assembly which controls cooling water flow from the upstream conduit portion to the downstream conduit portion to maintain a controlled engine temperature. The valve assembly controls engine temperature by permitting increased cooling water flow through the conduit as engine temperature or cooling water pressure increases, and decreased flow as engine temperature or water pressure decreases. The valve assembly can include a housing with an upstream inlet, a downstream outlet, and an opening between the inlet and the outlet. A thermostat in the housing is operable in response to upstream water temperature for opening and closing the opening and thereby permitting or preventing water flow through the housing. The housing is moveable into and out of engagement with a valve seat defining a second opening located between the upstream and downstream portions of the conduit to control water flow through the second opening in response to upstream coolant pressure, such as results from an increase in engine speed.
Attention is directed to the following U.S. Pat. Nos.:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 4,669,988 Breckenfeld et al. June 2, 1987 4,457,727 Flaig July 3, 1984 3,640,454 Freismuth et al. February 8, 1972 3,402,888 Kelly September 24, 1968 3,017,113 Drapeau January 16, 1962 ______________________________________